Transcript Vitiligo.ppt

Pigmentation
Disorders
Mechanism of pigment formation
UV
Epidermis
Melanocyte
Tyrosine
Tyrosinase
Melanin
Abnormal pigmentation
• Hyperpigmentation:
Cloasma, frekels
• Depigmentation:
A- Congenital: Albinism
B- Acquired: i- Vitiligo
ii- Secondary: burn, chemicals
Vitiligo
What is Vitiligo?
• Vitiligo is also called white
spot disease
• is a depigmentation disorder
characterized by the
development of white patches
in various parts, which are due
to the loss of melanocytes
from the epidermis
Symptoms &
• Vitiligo, particularly
in darker skinned
Signs
individuals, is a psychosocial disaster
• White patches of skin
• Whitening or graying of the hair on scalp,
eyelashes, eyebrows or beard
Etiology of Vitiligo
• Autoimmune disorder in which the body may be
destroying its own melanocytes
Predisposing factors:
• Heredity (over 30 %)
• Exposure to chemicals such as phenols
• Emotional or physical stress
• Skin injury, burns, inflammatory skin disorders
TREATMENT OF VITILIGO
Sunscreens should be used by all
patients with vitiligo to minimize risk of
sunburn or repeated solar damage to
depigmented skin
Use of a cosmetic cover-up solution
Re-pigmentation therapy: the
restoration of the normal pigment
Psoralen photochemotherapy
(Psorglen & Ultraviolet A Therapy & PUVA therapy)
• The patient is given
“
psoralen” (topically for
small, scattered patches less
than 20% or orally for
extensive vitiligo more than
20%)
Psoralen photochemotherapy
(Psorglen & Ultraviolet A Therapy & PUVA therapy)
• oral psoralen is taken about two
hours before exposure to UVA
light
• Then skin is carefully exposed to
sunlight or to ultraviolet A (UVA)
light that comes from a special
lamp ( 2-3 times a week)
Mechanism of
action of PUVA
• When psoralen is activated by UVA, it
stimulates re-pigmentation by increasing
the production of melanin from the amino
acid tyrosine by stimulating the activity of
the enzyme tyrosinase
Side effects of
PUVA
–Nausea, itching, blistering and painful
erythema
–Hyperpigmentation of the treated patches
or the normal skin surrounding the vitiligo
patches
–Accelerated skin ageing and increased risk
of skin cancer with long-term exposure to
the drug
Topical steroid
therapy
• Topical corticosteroids
are prescribed for
patients with small patches of vitiligo
• Cream must be applied to the white patches on
the skin for at least 3 months before seeing any
results
• Corticosteriod creams are not as effective as
psoralen photochemotherapy
• Side effects occur in areas where the skin is thin,
such as on the face and armpits
Topical immuno-modulators
• Tacrolimus ointment is effective for people with
small areas of depigmentation, especially on the face
and neck
• Tacrolimus acts on T cells and mast cells, inhibiting T
cell activation and the production of
proinflammatory cytokines
• This treatment may have fewer side effects than
corticosteroids. (does not cause atrophy)
• is well-tolerated when used for extended periods,
• There is concern that this may be associated with an
increased risk of skin cancer
Depigmentation
• Patients with vitiligo over half of their
exposed body may want to consider using this
method “ destruction of the remaining
melanocytes”
• A bleaching cream “hydroquinone”
(Benzoquin) is applied to normally pigmented
skin twice daily for 3-12 months
• Hydroquinone (HQ) acts by blocking the
synthesis of melanin by inhibition of
tyrosinase enzyme responsible for conversion
of tyrosine to melanin
• It should be used only when permanent
depigmentation is desired as it may lead to
irreversible depigmentation
• Burning or itching , allergic contact dermatitis
may occur